Make //content responsible for generating notification Ids

chrome/browser/notifications/notification_platform_bridge_mac.h

Index: chrome/browser/notifications/notification_platform_bridge_mac.h
diff --git a/chrome/browser/notifications/notification_platform_bridge_mac.h b/chrome/browser/notifications/notification_platform_bridge_mac.h
index b48f1896242ed15cd148a6a7da6496afe8c9acb1..5da7c947f9c5176aee98fb7df6ddb508cfb6f63c 100644
--- a/chrome/browser/notifications/notification_platform_bridge_mac.h
+++ b/chrome/browser/notifications/notification_platform_bridge_mac.h
@@ -39,7 +39,6 @@ class NotificationPlatformBridgeMac : public NotificationPlatformBridge {
   bool GetDisplayed(const std::string& profile_id,
                     bool incognito,
                     std::set<std::string>* notifications) const override;
-  bool SupportsNotificationCenter() const override;
 
   // Validates contents of the |response| dictionary as received from the system
   // when a notification gets activated.